Power supply device

ABSTRACT

A power supply device (104-1) includes a substrate (20) on which an electric component (25) is mounted, a chassis (10) having a chassis surface (11) and a threaded part (10a), a chassis-side resin part (91) connected to a back surface (20a) and the chassis surface (11), a fixation screw (29), and an insulating member (60). The fixation screw (29) fixes both the electric component (25) and the substrate (20) to the chassis (10) by screw-coupling an end part (29c) of the fixation screw (29), exposed in a direction toward the chassis (10) from an open hole formed through the insulating member (60), to the threaded part (10a) of the chassis (10). In addition, the fixation screw (29) brings the electric component (25) and the chassis (10) into electrical noncontact with each other by being placed in an open hole of the insulating member (60).

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is based on PCT filing of PCT/JP2018/024445,filed Jun. 27, 2018, the entire contents of which are incorporatedherein by reference. This application is also related to co-pending U.S.application Ser. No. 16/348,776, filed May 9, 2019, which is a U.S.National Phase application of PCT/JP2017/047296 filed Dec. 28, 2017, theentire contents of each are incorporated herein by its reference.

TECHNICAL FIELD

The present invention relates to a space power supply having a structurewith high heat dissipation that allows mounting of high-heat-generatingcomponents even with use of conventional substrates such as polyimidesubstrates or glass epoxy substrates.

BACKGROUND ART

Performance and a life of an electric component depend on heatgeneration from or an ambient temperature of the electric component.Particularly, electric components that are used in a vacuum areincapable of heat transfer through a medium of air or heat radiationinto air because there is no air for cooling around the electriccomponents, in contrast to on the ground. For a space power supply,therefore, design for heat dissipation from substrates to a chassis isimportant.

In recent years, additionally, increase in power of artificialsatellites has involved increase in power consumption by equipmentinstalled in the artificial satellites and thus has made technology ofthe design for the heat dissipation important. Particularly, FET (FieldEffect Transistor) and diodes for use in switching power supplies arehigh-heat-generating electric components. In a conventional measure forthe heat dissipation, such high-heat-generating electric components aremounted in positions on substrates that are near to screws for fixationto a chassis. Alternatively, such high-heat-generating electriccomponents are directly installed on the chassis and are electricallyconnected to patterns on the substrates with contrivance in lead bendingor contrivance in extension of interconnections to the substrates.

CITATION LIST Patent Literature

-   Patent Literature 1: JP 2014-53618-   Patent Literature 2: JP 2007-019125-   Patent Literature 3: JP 2000-332171-   Patent Literature 4: WO 2015/076050 pamphlet

Non-Patent Literature

-   Non-Patent Literature 1:    www.irf.com/technical-info/whitepaper/hermsmd.pdf “New Materials and    Technologies Solve Hermetic SMD Integration” [Searched on Dec. 27,    2016]

SUMMARY OF INVENTION Technical Problem

Such installation methods as mentioned above, however, have problems ofincrease in or loss of an inductance component due to elongation ofinterconnection paths, influences of EMC (ElectromagneticCompatibility), and increase in working processes during mounting.

Furthermore, there is a necessity for measures of increase in a numberof the screws for connection between the substrates and the chassis andplacement of the heat-generating components in positions that are asnear as possible to the screws for promotion of the heat dissipation andreduction in heat generation density through distribution with use of alarge number of components. Consequently, a problem of increase in sizesand mass of the power supplies has existed.

For power supply devices that are used in spacecraft such as artificialsatellites, additionally, measures against vibration and considerationfor exposure to radiation are demanded.

The present invention mainly aims at providing a simply-configured heatdissipation structure in a power supply device that prevents elongationof interconnection paths for heat-generating components and thatobviates necessity to increase a number of screws for connection betweensubstrates and a chassis.

The present invention additionally aims at providing a space powersupply device for which measures against vibration and measures againstradiation are employed.

Solution to Problem

A power supply device to be used in a spacecraft of the presentinvention includes:

a substrate on which an electric component is mounted on a mountingsurface;

a chassis having a chassis surface facing a back surface which is theopposite side of the mounting surface and a threaded part havingundergone threading;

a chassis-side resin part being an insulating resin-cured material to beplaced between the back surface of the substrate and the chassis surfaceso as to be connected to the back surface and the chassis surface, thecured insulating resin with a thermal conductivity between 1 W/mK and 10W/mK inclusive;

a fixation screw having a threaded shaft part; and

an insulating member through which an open hole in which the fixationscrew is to be placed is formed, wherein

open holes are formed through the electric component and the substrate,

the insulating member includes

-   -   a first placement part placed in a space formed by continuous        placement of the open hole of the electric component and the        open hole of the substrate and    -   a second placement part placed outside the open hole of the        electric component so as to be in contact with a peripheral edge        of the open hole of the electric component,

the fixation screw fixes both the electric component and the substrateto the chassis by screw-coupling an end part of the shaft part, exposedin a direction toward the chassis from the open hole of the insulatingmember, to the threaded part of the chassis and brings the electriccomponent and the chassis into electrical noncontact with each other bybeing placed in the open hole of the insulating member.

Advantageous Effects of Invention

The present invention includes the chassis-side resin part and is thuscapable of providing the power supply device having thesimply-configured heat dissipation structure.

In the power supply device of the present invention, additionally, thesubstrate and the electric component are fixed by the fixation screw tothe chassis through the insulating member. As a result, the space powersupply device having vibration resistance may be provided whileelectrical noncontact between the chassis and the electric component isensured.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating Embodiment 1 and a sectional view of apower supply device.

FIG. 2 is diagrams illustrating Embodiment 1 and a partial plan view andan E-E sectional view of a chassis.

FIG. 3 is a diagram illustrating Embodiment 1 and schematicallyillustrating a plan view of the power supply device.

FIG. 4 is a diagram illustrating Embodiment 2 and a sectional view of apower supply device.

FIG. 5 is a diagram illustrating Embodiment 2 and schematicallyillustrating a plan view of the power supply device.

FIG. 6 is a diagram illustrating Embodiment 3 and a sectional view of apower supply device.

FIG. 7 is a diagram illustrating Embodiment 4 and a sectional view of apower supply device.

FIG. 8 is a diagram illustrating Embodiment 4 and a sectional view ofthe power supply device.

FIG. 9 is a diagram illustrating Embodiment 5 and a sectional view of apower supply device.

FIG. 10 is a diagram illustrating Embodiment 6 and a sectional view of apower supply device.

FIG. 11 is a diagram illustrating Embodiment 7 and a sectional view of apower supply device.

FIG. 12 is a diagram illustrating Embodiment 7 and a sectional view ofthe power supply device.

FIG. 13 is a diagram illustrating Embodiment 8 and a sectional view of apower supply device.

FIG. 14 is diagrams illustrating Embodiment 9 and illustrating a methodof manufacturing a power supply device in atmosphere.

FIG. 15 is a diagram illustrating Embodiment 10 and a sectional view ofa power supply device 101-1.

FIG. 16 is a diagram illustrating Embodiment 10 and a sectional view ofa power supply device 101-2.

FIG. 17 is diagrams illustrating Embodiment 10 and a plan view and asectional view of a power supply device 102-1.

FIG. 18 is a diagram illustrating Embodiment 10 and a sectional view ofa power supply device 102-2.

FIG. 19 is a diagram illustrating Embodiment 10 and a sectional view ofa power supply device 102-3.

FIG. 20 is a diagram illustrating Embodiment 10 and a sectional view ofa power supply device 102-4.

FIG. 21 is a diagram illustrating Embodiment 11 and a sectional view ofa power supply device 103.

FIG. 22 is a diagram illustrating Embodiment 12 and a sectional view ofa power supply device 104-1.

FIG. 23 is a diagram illustrating Embodiment 12 and a sectional view ofa power supply device 104-2.

FIG. 24 is a diagram illustrating Embodiment 12 and a sectional view ofa power supply device 104-3.

FIG. 25 is a diagram illustrating Embodiment 12 and a sectional view ofa power supply device 104-4.

FIG. 26 is a diagram illustrating Embodiment 12 and a sectional view ofa power supply device 104-5.

FIG. 27 is a diagram illustrating Embodiment 12 and a sectional view ofa power supply device 104-6.

FIG. 28 is a diagram illustrating Embodiment 12 and a fragmentaryenlarged view illustrating a configuration of type A1.

FIG. 29 is a diagram illustrating Embodiment 12 and a fragmentaryenlarged view illustrating a configuration of type A2.

FIG. 30 is a diagram illustrating Embodiment 12 and a fragmentaryenlarged view illustrating a configuration of type A3.

FIG. 31 is a diagram illustrating Embodiment 12 and a fragmentaryenlarged view illustrating a configuration of type B1.

FIG. 32 is a diagram illustrating Embodiment 12 and a fragmentaryenlarged view illustrating a configuration of type B2.

FIG. 33 is a diagram illustrating Embodiment 12 and a sectional view ofa power supply device 104-7.

FIG. 34 is a diagram illustrating Embodiment 12 and illustratingadjustment in radiation dose.

DESCRIPTION OF EMBODIMENTS

Hereinbelow, embodiments of the present invention will be described withuse of the drawings. In the drawings, identical parts or correspondingparts are provided with identical reference characters. In descriptionon the embodiments, description on the identical parts or thecorresponding parts are omitted or simplified appropriately. AsEmbodiments 1 to 8, space power supply devices 100 having differentconfigurations will be described. Hereinbelow, the space power supplydevices 100 will be referred to as power supply devices 100.

The power supply devices 100 may have one of the configurations ofEmbodiments 1 to 8 or may have a plurality of configurations among theconfigurations of Embodiments 1 to 8.

In the embodiments below, the power supply devices 100 are distinguishedby addition of “−1” as in a power supply device 100-1, for instance.

Embodiment 1

***Description of Configuration***

With reference to FIGS. 1 to 3 , the power supply device 100-1 ofEmbodiment 1 will be described. The power supply device 100-1 may beused in a vacuum or a near-vacuum environment on the ground.

FIG. 1 is a sectional view of the power supply device 100-1. Therein, anelectric component 25 and a screw are not illustrated in sections. InFIG. 1 , xyz coordinate system is illustrated. The same coordinatesystem is illustrated for Embodiments 2 to 9. FIGS. 4 and 6 to 14 thatare sectional views of Embodiments 2 to 9 illustrate sections of thesame site as is illustrated in FIG. 1 .

The power supply device 100-1 includes a chassis 10, a substrate 20 onwhich the electric component 25 is mounted and which is fixed to thechassis 10, and a fixation part 30 to fix the substrate 20 to thechassis 10. In the power supply device 100-1, the fixation part 30 is asubstrate fixation screw 31.

FIG. 2 illustrates a partial plan view (view in an arrow direction −Z inFIG. 1 ) and an E-E section of the chassis 10. The E-E sectioncorresponds to FIGS. 1, 4, 6 to 16, and 21 . The substrate fixationscrew 31 is screwed into a screw hole 12. In FIG. 1 , a portion of thechassis 10 and a portion of the substrate 20 are illustrated. Aplurality of screw holes 12 exist on the chassis 10. The substratefixation screw 31 is screwed into each of the screw holes 12. Aplurality of substrate fixation screws 31 and the plurality of screwholes 12 are placed on a peripheral edge part along a perimeter of thesubstrate 20 and are provided at specified intervals in four corners oron four sides of a rectangle, for instance.

FIG. 3 is a diagram schematically illustrating a view of a portioncorresponding to an area 13 in FIG. 2 , that is, FIG. 1 in the arrowdirection −Z.

In the power supply device 100-1 of FIG. 1 , the substrate 20 on whichthe electric component 25 is mounted is fixed to the chassis 10.Electrodes 26 of the electric component 25 are connected to a C surfaceof the substrate 20 that is the other surface 20 b on a back side of onesurface 20 a. Filled through-holes 21 to be described later are formedon the substrate 20. In FIG. 1 , the filled through-holes 21 numberingin ten are illustrated. Heat 8 represented by arrows and generated inthe electric component 25 is conducted from the filled through-holes 21via cured insulating resin 27-1 to be described later to a chassissurface 11.

Thus the power supply device 100-1 includes the substrate 20, thechassis 10, and the cured insulating resin 27-1 that is a chassis-sideresin part 91 and the electric component 25 is mounted on the substrate20. The chassis 10 has the chassis surface 11 that is a surface facingthe one surface 20 a of the substrate 20. The cured insulating resin27-1 is placed between the one surface 20 a of the substrate 20 and thechassis surface 11. The cured insulating resin 27-1 is cured insulatingresin connected to the one surface 20 a and the chassis surface 11 andhaving a thermal conductivity between 1 W/mK and 10 W/mK inclusive.

(Substrate 20)

The electric component 25 that generates a large quantity of heat isinstalled on the substrate 20. In the embodiment, an FET of SMD (SurfaceMount Device) type is used as the electric component 25 that generatesthe large quantity of heat. Ordinarily, heat generated in an FET of SMDtype is conducted from electrodes of the FET to a circuit pattern on thesubstrate 20, then conducted in in-plane directions, and conductedthrough screw fastening parts to the chassis 10.

(Filled Through-Hole)

In the power supply device 100-1, potting (molding) between an S surfacethat is the one surface 20 a of the substrate 20 and the chassis surface11 of the chassis 10 is attained with use of a highly thermal conductiveinsulating resin composition (uncured insulating resin 27-1) asillustrated in FIG. 1 . Thus the heat of the electric component 25 isconducted to the chassis 10 through highly thermal conductive pottingresin that is the insulating resin composition, as paths. Thethrough-holes penetrating from the C surface to the S surface of thesubstrate 20 are provided in order to improve thermal conduction in athickness direction (from the C surface that is the other surface 20 bto the S surface) in the substrate 20. The through-holes are plated.Inside of the plated through-holes is filled with solder, another metal,or potting resin having high thermal conductivity. The through-holes arereferred to as the filled through-holes 21.

Thus the substrate 20 includes the filled through-holes 21 in which thethrough-holes penetrating from the one surface 20 a to the other surface20 b are filled with heat transfer material. The cured insulating resin27-1 is connected to one end part 21 a of each of the filledthrough-holes 21 that appears on the one surface 20 a. The heat transfermaterial that fills the filled through-holes 21 is metal, curedinsulating resin having a thermal conductivity between 1 W/mK and 10W/mK inclusive, or the like.

Subsequently, characteristics of the cured insulating resin 27-1 and theinsulating liquid resin composition from which the cured insulatingresin 27-1 is made will be described. For the cured insulating resin27-1, silicone or urethane is used as base resin, though details will bedescribed below. The cured insulating resin 27-1 contains at least oneof alumina, boron nitride, aluminum nitride, magnesium oxide, andberyllium oxide, as inorganic filler, and has a Shore A hardness of 70or less, a low-molecular component volatilization volume of 1000 ppm orless with 300° C. heating, and a glass transition point of −20° C. orlower.

Examples of methods of forming the highly thermal conductive curedinsulating resin 27-1 between the S surface of the substrate 20 and thechassis 10 include methods (1) and (2) below.

(1) There is the formation method in which the substrate 20 is fixed tothe chassis 10, thereafter the insulating liquid resin composition ispoured into between the chassis 10 and the substrate 20, and theinsulating resin composition is cured by heat.

(2) Alternatively, the cured insulating resin 27-1 is formed on a bottomsurface of the chassis 10 and the substrate 20 is thereafter fixed tothe chassis 10 by the substrate fixation screw 31. In the method (2), athickness L2 of the cured insulating resin 27-1 at time beforeinstallation of the substrate 20 on the chassis 10 is formed so as to bein a range between 110% and 250% inclusive of a width L1 between the Ssurface (the one surface 20 a) of the substrate 20 and the chassissurface 11 of the chassis 10, depending on the hardness of the curedinsulating resin 27-1.That is,L2=(1.1 to 2.5)×L1holds. More preferably, the thickness L2 of the cured insulating resin27-1 at time before the installation of the substrate 20 on the chassis10 is in a range between 120% and 200% inclusive of the width L1.That is,L2=(1.2 to 2.0)×L1holds. On condition that the thickness L2 of the cured insulating resin27-1 is formed in the range, an interface between the S surface and thecured insulating resin 27-1 is brought into more tight and intimatecontact by the fixation part 30 for the substrate 20, so that an effectof the heat dissipation may be enhanced. Furthermore, deterioration ofthe heat dissipation in case of decrease in the thickness due tocooling-heating cycles in a usage environment may be reduced. Oncondition that the thickness of the cured insulating resin 27-1 issmaller than 110% of the width between the S surface and the chassissurface 11,that is, on condition thatL2<1.1×L1holds, the effect of the heat dissipation is deteriorated by thedecrease in the thickness of the cured insulating resin 27-1 due to thecooling-heating cycles.On condition that the thickness L2 exceeds 200% of the thickness L1,that is, on condition thatL2>2.0×L1holds, there is a fear that the substrate 20 may be deformed when thesubstrate 20 is fixed to the chassis 10 by the screws and that thesubstrate 20 may be cracked in the cooling-heating cycles because ofsuch deformation.

In the above methods (1) and (2), the cured insulating resin 27-1 may beformed by pouring of the insulating liquid resin composition with the Ssurface of the substrate 20 directed upward (in +Z direction). In thisprocess as well, the thickness L2 of the cured insulating resin is madeas large as the thickness described in relation to the above method (2).

Subsequently, the substrate 20 is fixed to the chassis 10 by the screwsso that the cured insulating resin 27-1 having been formed comes intocontact with the chassis 10. This fixation prevents bubbles to beinsulation weak points from remaining on high-voltage sites such asinterconnection pattern on the S surface.

(Insulating Resin Composition and Hardness)

The insulating resin composition is the insulating liquid resincomposition containing at least one of alumina, boron nitride, aluminumnitride, magnesium oxide, and beryllium oxide, as the inorganic fillerproviding high thermal conductivity, in insulating liquid resin.

That is,

<insulating liquid resin composition=[insulating liquid resin+inorganicfiller]>+thermal curing→cured insulating resin 27-1 holds. The hardnessof the cured insulating resin 27-1 obtained through curing of theinsulating liquid resin composition is 80 or less (Shore A) or is 70 orless, more preferably.

On condition that the hardness exceeds 80, there are a fear that theeffect of the heat dissipation may not be obtained because ofdeterioration in adhesion to the substrate 20 and a fear that thesubstrate 20 may be deformed.

The hardness is indicated with use of a Shore A scleroscope as arepresentative. Soft materials may be measured with use of Shore E,Shore 00, ASKER C, or the like. On condition that the Shore A hardnessis 80 or less, such measurement may be carried out with use of Shore E,Shore 00, ASKER C, or the like.

(Low-Molecular Component Content in Cured Material)

The cured insulating resin 27-1 is cut into small pieces, from whichcomponents of the cured insulating resin 27-1 are extracted with use ofan organic solvent such as hexane or acetone. With use of a gaschromatography mass spectrometer (GC/MS) and helium as carrier gas,amounts of low-molecular components are analyzed while a temperature ofthe extraction solvent is increased from 40° C. to 300° C. The amountsof low-molecular components are 2000 ppm or less or 1000 ppm or less,preferably.

In excess of 2000 ppm, there is a fear that contamination of theelectric component and interconnections, an electrical contact fault, ordeterioration in characteristics of the electrical component may becaused by the cooling-heating cycles in use of the cured insulatingresin 27-1.

(Outgas from Cured Material)

The cured insulating resin 27-1 is tested in a vacuum environment(7×10⁻³ Pa or lower) and under test conditions of a heating temperatureof 125° C., retention time of 24 hours, and an emitted gas coolingtemperature of 25° C., in conformity with ASTM E595. Measurement foroutgas emitted from the cured insulating resin 27-1 under the testconditions is carried out.

Total Mass Loss (TML) calculated from results of the measurement shouldbe 1% or less and Collected Volatile Condensable Material (CVCM)calculated from the same should be 0.1% or less.

On condition that TML exceeds 1% or that CVCM exceeds 0.1%, there is afear that the contamination of the electric component and theinterconnections, an electrical contact fault, or the deterioration inthe characteristics of the electrical component may be caused by thecooling-heating cycles in the use.

(Glass Transition Point)

The glass transition point of the cured insulating resin 27-1 is −10° C.or lower or −20° C. or lower, preferably. More preferably, the glasstransition point is a temperature that is lower than a lower side oftemperatures of the cooling-heating cycles in the use of the curedinsulating resin 27-1. On condition that the glass transition point ishigher than −10° C., there is a fear that unattainability for stableheat dissipation, warpage of the substrate 20, or the like may be causedby increase in deformation of the cured insulating resin 27-1, in thecooling-heating cycles in the use of the cured insulating resin 27-1.

(Insulating Liquid Resin)

The insulating liquid resin may be thermosetting liquid resin such assilicone resin or urethane resin.

(Silicone Resin)

As the silicone resin, publicly known silicone resin may be used as longas the silicone resin is liquid at a room temperature. A curing systemfor the silicone resin may be of either addition reaction type orcondensation reaction type. The silicone resin may be rubbery(elastomeric) or gelled after being cured.

A base polymer has an average molecular weight between 5,000 and 100,000and is liquid having a viscosity between 1 Pa·s and 100,000 Pa·s at 25°C., for instance. The base polymer is publicly known organopolysiloxanehaving at least one kind of alkyl group, alkenyl group, allyl group,hydroxyl group, hydrogen group, alkoxyalkyl group, and alkoxysilyl groupin side chains and at ends and having a linear, cyclic, branched, orladder-like main chain structure. The base polymer may be a mixture oftwo or more kinds of organopolysiloxane.

In the addition reaction type, a composition containingorganopolysiloxane including alkenyl group as the base polymer, hydrogensiloxane as a crosslinking agent, and a platinum compound as a catalystmay be used. Amounts of those may be publicly known effective amountsthat result in advance in a curing reaction and obtainment of a hardnessrequired after the curing.

In the condensation reaction type, a composition containingorganopolysiloxane including silanol group as the base polymer, a silanecompound such as alkoxysilane or acetoxysilane as the crosslinkingagent, and an organotin compound as the catalyst may be used.

Amounts of those may be conventionally and publicly known effectiveamounts that result in the advance in the curing reaction and theobtainment of the hardness required after the curing.

(Urethane Resin)

The urethane resin is a resin having a urethane bond in a compositionobtained by combination and copolymerization of polyol resin having aplurality of hydroxyl groups in one molecule as a main agent and acompound having two or more isocyanate groups in one molecule as acuring agent.

As the urethane resin, publicly known urethane resin may be used as longas the urethane resin is liquid having a viscosity between 1 Pa·s and100,000 Pa·s at 25° C. after being mixed.

As the polyol resin, for instance, polyester-based polyol,dicarboxylate-based polyol, polyether-based polyol, polytetramethylenepolyoxyglycol, castor-oil-based polyol, ε-caprolactone-based polyol,polyoxypolyalkylene-based polyol, β-methyl-δ-valerolactone-based polyol,carbonate-based polyol, or the like that are publicly known may be usedor two or more kinds thereamong may be used in combination.

As the isocyanate compound, tolylene diisocyanate, naphthalenediisocyanate, hexamethylene diisocyanate, xylidine diisocyanate,diphenylmethane diisocyanate, isophorone diisocyanate, cyclohexyldiisocyanate, or the like that are publicly known may be used or two ormore kinds thereamong may be used in combination.

An appropriate urethanization catalyst may be used in order to promote aurethanization reaction. As the urethanization catalyst, a publiclyknown catalyst such as tertiary amine compound or organometalliccompound may be used. As urethanization catalysts, triethylenediamine,N, N′-dimethylhexamethylenediamine, N, N′-dimethylbutanediamine,diazabicyclo(5, 4, 0) undecene-7(DBU) and DBU salt, lead octylate,dibutyltin laurate, bismuth tris(2-ethyl hexanoate), titaniumdiisopropoxy bis(ethyl acetoacetate), and the like may be enumerated,for instance.

A formulation of the polyol and the isocyanate compound is calculatedfrom an equivalence ratio of the isocyanate groups (NCO) of theisocyanate to the hydroxyl groups (OH) of the polyol. The equivalenceratio (NCO/OH) is not to be particularly specified but is preferably ina range between 0.95 and 1.05. It is undesirable for the equivalenceratio to exceed 1.05, because the hardness of the cured insulating resincomposition is increased. In addition, it is undesirable because carbondioxide as a by-product makes void remain in the cured material and thusdeteriorates insulation characteristics. On the other hand, it isundesirable for the equivalence ratio to be less than 0.95, because slowprogress in the curing reaction is prone to result in uncured materialand insufficient production stability. Besides, it is undesirablebecause of insufficient heat resistance.

(Filler for Obtainment of Thermal Conductivity)

The filler having the thermal conductivity has a role of providing thecomposition (cured material) with the thermal conductivity and athermally conductive filler that is publicly known may be used as thefiller. As examples of the filler, alumina powder, magnesium oxidepowder, boron nitride powder, aluminum nitride powder, beryllium oxidepowder, zinc oxide powder, silicon nitride powder, silicon oxide powder,aluminum powder, copper powder, silver powder, nickel powder, goldpowder, diamond powder, carbon powder, indium, gallium, and the like maybe enumerated.

On condition that it is necessary to ensure not only thermal paths butalso insulation performance between the substrate 20 and the chassis 10,powder providing high insulation performance, such as alumina powder,magnesium oxide powder, boron nitride powder, aluminum nitride powder,beryllium oxide powder, or silicon oxide powder is preferably used.

As the thermally conductive filler, one kind of such filler may besolely used or two or more kinds of such filler may be mixed to be used.The thermally conductive filler preferably has a thermal conductivityequal to or higher than 10 W/m·K. That is because the thermalconductivity lower than 10 W/m·K makes it impossible to provide asufficient thermal conductivity for the composition (cured material). Anaverage particle size of the filler to provide the thermal conductivityis between 0.1 μm and 200 μm inclusive, or

between 0.5 μm and 100 μm inclusive, preferably.

As the thermally conductive filler having such an average particle size,one kind of such filler may be solely used or two or more kinds of suchfiller having different particle sizes may be mixed to be used. Thethermally conductive filler having an average particle size smaller than0.1 μm is undesirable because particles may be made prone to aggregateand poor in liquidity. The thermally conductive filler having an averageparticle size larger than 100 μm is undesirable because particles may bemade prone to settle and because the thermal conductivity of the curedmaterial may be consequently made nonuniform.

A form of the filler may be amorphous or spherical or any form isallowed. The average particle size may be measured as an average volumevalue D50 (that is, a particle size or a median size at time when anaccumulated volume is 50%) in a particle size distribution measurementby laser diffractometry.

(Insulating Liquid Resin Composition)

The insulating resin composition is obtained by mixture of the inorganicfiller, providing the high thermal conductivity, with the insulatingliquid resin. Increase in an amount of the filler causes increase in thethermal conductivity of the cured material. Then workability isdeteriorated by increase in viscosity of the composition or adhesion tothe substrate is deteriorated by increase in the hardness of the curedmaterial. As a result, the effect of the heat dissipation as a targetmay not be obtained.

Therefore, a ratio of the inorganic filler contained in the insulatingliquid resin composition is not particularly confined as long as theviscosity of the insulating resin composition blended with the inorganicfiller is equal to or lower than 300 Pas at 25° C.

In case where the insulating resin composition is required to be pouredinto a narrow gap, it is desirable for the viscosity to be equal to orlower than 50 Pa·s. The inorganic filler is preferably in a range

between 40 vol % and 80 vol % inclusive, or

more preferably in a range

between 50 vol % and 75 vol % inclusive, for instance.

It is undesirable for the ratio to exceed 80 vol % because theworkability may be deteriorated by the increase in the viscosity of theinsulating resin composition or because stable heat dissipationcharacteristics may not be obtained due to the increase in the hardnessof the cured material. On the other hand, it is undesirable for theinorganic fuller to be lower than 40 vol % because improvement in thethermal conductivity of the cured material may not be expected due to ahigh ratio of the resin. In order to control reactivity of theinsulating resin composition or the adhesion to the substrate, anadditive such as a reaction controlling agent such as an acetylenecompound, various nitrogen compounds, an organophosphorus compound, anoxime compound, and an organochloro compound or an adhesion modifyingagent such as silane coupling agent may be appropriately added asrequired.

(Curing Conditions)

Curing conditions for the insulating liquid resin composition may besimilar to curing conditions for silicone potting material or urethanepotting material that are publicly known.

A curing temperature is

preferably from the room temperature to 180° C. or less or

more preferably

from the room temperature to 150° C. or less.

On condition that the curing temperature is equal to or lower than theroom temperature, there is a fear that insufficient curing may result involatilization of unreacted raw materials in the cooling-heating cyclesin the use and the contamination of the electric component. On conditionthat the curing temperature exceeds 150° C., there is a fear that thetemperature may exceed a heat-resistance temperature for the electriccomponent and may thereby cause deterioration of the electric component.

Though curing time is not confined as long as the required hardness isattained, the curing time at the room temperature is

48 hours or shorter time or, preferably,

24 hours or shorter time or

the curing time in thermal curing is

between 0.1 hours and 12 hours inclusive or,

preferably,

between 0.5 hours and 6 hours inclusive.

In case where there is a concern about outgas in the use of the curedinsulating resin 27-1, the thermal curing is preferably carried out. Bya heating process at an upper limit allowable temperature for theelectric component, for instance, the low-molecular components in thecured material that are volatile may be decreased and adverse effects ofthe outgas may be avoided.

A breakdown field of the cured insulating resin composition ispreferably equal to or stronger than 10 kV/mm or more preferably equalto or stronger than 15 kV/mm.

The breakdown field weaker than 10 kV/mm may necessitate increasingdistances between interconnections for the electric component anddistances between interconnection patterns on the substrate 20,depending on a working voltage, and may decrease a contribution ofdecrease in sizes of power supply members.

(Volume Resistivity of Cured Insulating Resin)

A volume resistivity of the cured insulating resin composition ispreferably 1.0E+10 Ω·cm or more or, more preferably,

1.0E+12 Ω·cm or more.

The volume resistivity lower than 1.0E+10 Ω·cm

may necessitate increasing the distances between the interconnectionsfor the electric component and the distances between the interconnectionpatterns on the substrate 20, depending on the working voltage, and maydecrease the contribution of the decrease in the sizes of the powersupply members. Before potting of the insulating liquid resincomposition onto heat-generating components or the substrate or pouringof the insulating liquid resin composition into an enclosure, thoseadherends may be treated with surface modifier (primer) to improve theadhesion. A publicly known primer for silicone or for urethane may beused.

In summary of methods of manufacturing the power supply device 100-1, amanufacturing method of pouring the resin into between the substrate 20and the chassis 10 is as follows.

The method of manufacturing the power supply device 100-1 includes

a substrate placement step of placing the substrate 20 with respect tothe chassis surface 11 so that the one surface 20 a of the substrate 20may face the chassis surface 11,

a pouring step of pouring the insulating liquid resin composition intobetween the one surface 20 a of the substrate 20 and the chassis surface11, and

a curing step of forming the chassis-side resin part 91 by curing thepoured liquid resin composition.

In the liquid resin composition, silicone or urethane is used as thebase resin and at least one of alumina, boron nitride, aluminum nitride,magnesium oxide, and beryllium oxide is contained as the inorganicfiller.

The hardness of the chassis-side resin part 91 is preferably 70 or lessin Shore A hardness. Preferably, the chassis-side resin part 91 has thelow-molecular component volatilization volume of 1000 ppm or less in300° C. heating and has the glass transition point of −20° C. or lower.

A summary of a method of manufacturing the power supply device 100-1 inwhich the substrate 20 is installed onto the chassis 10 after curing ofthe resin is as follows.

The method of manufacturing the power supply device 100-1 includes apouring step of pouring the insulating liquid resin composition onto thechassis surface 11,

a curing step of forming the chassis-side resin part 91 by curing theliquid resin composition poured onto the chassis surface 11, and

an installation step of installing the substrate 20 onto the chassis 10so that the one surface 20 a of the substrate 20 may face the chassissurface 11 and may come into intimate contact with the chassis-sideresin part 91.

In the liquid resin composition,

silicone or urethane is used as the base resin and at least one ofalumina, boron nitride, aluminum nitride, magnesium oxide, and berylliumoxide is contained as the inorganic filler.

The hardness of the chassis-side resin part 91 is preferably 70 or lessin Shore A hardness. Preferably, the chassis-side resin part 91 has thelow-molecular component volatilization volume of 1000 ppm or less in300° C. heating and has the glass transition point of −20° C. or lower.

In both of the manufacturing method, the viscosity of the liquid resincomposition is preferably equal to or lower than 300 Pa·s at 25° C.

Embodiment 2

With reference to FIGS. 4 and 5 , a power supply device 100-2 ofEmbodiment 2 will be described.

FIG. 4 is a sectional view of the power supply device 100-2. FIG. 5 is adiagram corresponding to FIG. 3 and a schematic diagram equivalent to aview in an arrow direction −Z in FIG. 4 .

In the power supply device 100-2, in contrast to the power supply device100-1, an electric component 25 such as TO-254 package in which leads asthe electrodes 26 are formed is used as a space power MOSFET. In thepower supply device 100-2, the electric component 25 that is aheat-generating component is TO-254. The power supply device 100-2differs from the power supply device 100-1 in (1) to (3) below. Theother configurations are the same as configurations of the power supplydevice 100-1.

(1) In a configuration, the filled through-holes 21 are provideddirectly beneath the electric component 25 so as to conduct the heat tothe S surface of the substrate 20.

(2) Between a bottom surface of the electric component 25 and thesubstrate 20, thermally-conductive material 23 is placed in order toefficiently conduct the heat 8 of the electric component 25 to thefilled through-holes 21. The thermally-conductive material 23 is solderpaste or silver paste, for instance.(3) The electric component 25 is fixed to the substrate 20 by a fixationscrew 29.

Ordinarily, the electric component 25 of the same type to be used forspace has a design for heat dissipation in which a semiconductor ismounted in a position adjacent to a surface to be in contact with thesubstrate 20 or the chassis 10 and the like in the electric component 25(in the package). Therefore, the heat may be efficiently dissipated tothe chassis 10 by the configurations of FIG. 4 . Filling of thethrough-holes with solder, another metal, or thermally conductive resinand pouring of the resin having high thermal conductivity into betweenthe S surface of the substrate 20 and the chassis 10, other than (1) to(3) mentioned above, are the same as in Embodiment 1.

Embodiment 3

With reference to FIG. 6 , a power supply device 100-3 of Embodiment 3will be described.

FIG. 6 is a diagram for description of the power supply device 100-3. Incontrast to the power supply device 100-1, the power supply device 100-3has a configuration with potting of a head of the substrate fixationscrew 31 with resin 27-2 having high thermal conductivity. The otherconfigurations of the power supply device 100-3 are the same as theconfigurations of the power supply device 100-1.

In space, gases such as air do not exist around the power supply device100-3 in such a quantity as to influence heat conduction and thus heatgenerated from the substrate 20 is dissipated to the chassis 10 throughthe substrate fixation screw 31 that fixes the substrate 20. Due toabsence of the gases such as air, however, the heat is dissipated onlyfrom a contact area formed between the substrate 20 and the chassis 10by pressure of the substrate fixation screw 31. Therefore, a number ofthe screws needs to be increased as the quantity of the heat increases.Paths for the heat dissipation may be enhanced by coverage of an endpart of the substrate 20 including the substrate fixation screw 31 andthe chassis 10 with the resin 27-2 having the high thermal conductivityas the potting material. The same resin as the cured insulating resin27-1 may be used as the resin 27-2 in this example. In a configurationin which the plurality of screw holes 12 exist on the chassis 10 and inwhich the substrate fixation screws 31 are screwed into the screw holes12, as stated in description on FIG. 2 , the heads of the substratefixation screws 31 may be covered with the resin 27-2. The plurality ofsubstrate fixation screws 31 and the plurality of screw holes 12 areplaced on the peripheral edge part along the perimeter of the substrate20 and are provided at specified intervals in the four corners or on thefour sides of the rectangle, for instance.

Embodiment 4

FIGS. 7 and 8 are diagrams illustrating a power supply device 100-4 ofEmbodiment 4. The power supply device 100-4 of FIGS. 7 and 8 is the sameas the power supply device 100-1, except that a configuration of thefixation part 30 differs from that of the power supply device 100-1.

The power supply device 100-4 illustrated in FIG. 7 has a configurationincluding a spring fixture 33 having spring characteristics between thesubstrate 20 and the chassis 10. In general, a coefficient of thermalexpansion of the cured insulating resin 27-1 is several hundred ppm,which is greater than that of metal from several ppm to tens of ppm.When changes in sizes such as thickness and width of the curedinsulating resin 27-1 filled between the chassis 10 and the substrate 20are caused by the heat, therefore, the spring fixture 33 makes itpossible for the substrate 20 to follow the change of the curedinsulating resin 27-1. As a result, separation between the substrate 20and the cured insulating resin 27-1 may be reduced. Though the substrate20 and the spring fixture 33 are connected by solder 32 a in FIG. 7 ,the substrate 20 and the spring fixture 33 may be fastened by a screw 32b as in the power supply device 100-4 of FIG. 8 . The plurality ofsubstrate fixation screws 31 and a plurality of spring fixtures 33 areplaced on the peripheral edge part along the perimeter of the substrate20 and are provided at specified intervals in the four corners or on thefour sides of the rectangle, for instance.

Embodiment 5

FIG. 9 is a diagram illustrating a power supply device 100-5 ofEmbodiment 5. The power supply device 100-5 differs from the powersupply device 100-1 in (1) to (3) below. The other configurations arethe same as the configurations of the power supply device 100-1.

(1) The electrodes 26 of the electric component 25 are on top of theelectric component 25.

(2) The electrodes 26 and the filled through-holes 21 are connected bywires or bus bars that are electrode connection parts 28-1.

(3) The electric component 25 is fixed to the substrate 20 by adhesive24.

In the electric component 25 mounted on the substrate 20, in general,the electrodes 26 are directly connected to the circuit pattern on thesubstrate 20. In case where the substrate 20 and the electric component25 greatly differ in the coefficient of thermal expansion, however,soldered parts may be cracked in thermal cycles. Therefore, a method maybe adopted including daringly orienting the electrodes 26 of theelectric component 25 in an upward direction opposite to the substrate20, connecting the wires or the bus bars as electrode extension parts tothe electrodes 26 oriented upward, and connecting the wires or the busbars to the circuit pattern on the substrate 20. In such aconfiguration, the heat dissipation is enabled by connection of thewires or the bus bars to the filled through-holes 21.

In order to attain the heat dissipation, in FIG. 9 , the wires or thebus bars are used as the electrode connection parts 28-1 that are heattransfer material to connect the electrodes 26 and the filledthrough-holes 21.

Embodiment 6

FIG. 10 is a diagram illustrating a power supply device 100-6 ofEmbodiment 6. In contrast to the power supply device 100-5, the powersupply device 100-6 has a configuration in which the electric component25 and the electrode connection parts 28-1 that are the bus bars or thewires are enclosed in cured resin 27-3. The configuration may improvethe thermal conductivity. The cured resin 27-3 forms a component-sideresin part 92.

As illustrated in FIG. 10 , the filled through-holes 21 are placed insome positions around the electric component 25 on the substrate 20. Thecured resin 27-3 is placed in a position opposed to the cured insulatingresin 27-1 with respect to the substrate 20 so that the substrate 20 isinterposed between the cured resin 27-3 and the cured insulating resin27-1 that is the chassis-side resin part 91. The cured resin 27-3 iscured insulating resin to seal in the electric component 25, the otherend part 21 b of each of the filled through-holes 21 that appears on theother surface 20 b of the substrate 20, and the electrode connectionparts 28-1. The same resin as the cured insulating resin 27-1 may beused as the cured resin 27-3.

Embodiment 7

FIGS. 11 and 12 are diagrams illustrating a power supply device 100-7 ofEmbodiment 7. In contrast to the power supply device 100-6, the powersupply device 100-7 illustrated in FIG. 11 has a configuration in whicha bus bar for the heat dissipation that is a chassis connection part28-2 is provided above the electric component 25. The chassis connectionpart 28-2 is fixed to the chassis 10 by a screw 42. The heat dissipationmay be increased by the bus bar for the heat dissipation. In thisexample, the cured resin 27-3 of FIG. 11 forms a contact resin part 93that is cured insulating resin.

FIG. 12 illustrates a configuration in which cured resin 27-4 that isthe contact resin part 93 is placed on the top of the electric component25. Though the electric component 25 of FIG. 12 includes the electrodes26 similar to the electrodes 26 of the electric component 25 to bedescribed later and illustrated in FIG. 13 , a direction in which theelectrodes 26 are arranged is Y direction in FIG. 12 and is X directionin FIG. 13 . The same resin as the cured insulating resin 27-1 may beused as the cured resin 27-4. The configuration of FIG. 12 enables theheat dissipation from an upper part of the electric component 25, suchas a transformer or an IC of SMD type, the upper part which is opposedto the substrate 20 and on which the cured resin 27-4 is molded.

As illustrated in FIGS. 11 and 12 , the substrate 20 is interposedbetween the contact resin part 93 and the cured insulating resin 27-1that is the chassis-side resin part 91.

The contact resin part 93 is placed in a position opposed to the curedinsulating resin 27-1 with respect to the substrate 20 so as to be incontact with at least a portion of the electric component 25. Thechassis connection part 28-2 having heat transference connects thecontact resin part 93 and the chassis 10.

Embodiment 8

FIG. 13 is a diagram illustrating a power supply device 100-8 ofEmbodiment 8. In the power supply device 100-7, the chassis connectionpart 28-2 that is the bus bar provided for the heat dissipation isconnected to the chassis 10.

In the power supply device 100-8, a through-hole connection part 28-3 isconnected to the other end part 21 b of each of the filled through-holes21 on the substrate 20. Thus the heat 8 is dissipated through the curedinsulating resin 27-1 to the chassis 10. As a result, paths for the heatdissipation may be made shorter than the paths for the heat dissipationin the power supply device 100-7 of FIG. 12 .

That is, the filled through-holes 21 are placed in some positions aroundthe electric component 25 on the substrate 20, as illustrated in FIG. 13. The substrate 20 is interposed between the contact resin part 93 andthe cured insulating resin 27-1 that is the chassis-side resin part 91.The contact resin part 93 is placed in a position opposed to the curedinsulating resin 27-1 with respect to the substrate 20 so as to be incontact with at least a portion of the electric component 25. Thethrough-hole connection part 28-3 connects the contact resin part 93 andthe other end part 21 b of each of the filled through-holes 21.

Embodiment 9

FIG. 14 is diagrams representing Embodiment 9. Embodiment 9 relates to amethod of manufacturing the power supply device 100 in an environmentwhere atmosphere exists. Embodiment 9 sets forth a work of forming alayer of the cured insulating resin 27-1 (insulating resin composition)between the substrate 20 and the chassis 10, that is, a work ofinjecting the insulating liquid resin composition, not in a vacuum butin a common atmospheric environment on the ground.

Though the power supply device 100-8 is used as an example in Embodiment9, the method of Embodiment 9 may be applied to the power supply devices100-1 to 100-7.

(a) of FIG. 14 illustrates the desirable manufacturing method in theatmospheric environment and (b) of FIG. 14 illustrates an undesirablemanufacturing method in the atmospheric environment. In (a) and (b) ofFIG. 14 , airflow is illustrated by arrows 44. In (a) of FIG. 14 ,bubbles are directed in an upward Z direction from the insulating liquidresin composition due to a difference in specific gravity between theinsulating liquid resin composition and the bubbles, that is, air, sothat the bubbles go out into the atmosphere. Therefore, a probability ofengulfing the air is decreased. On the other hand, in (b) of FIG. 14 ,air moving upward, that is, in Z direction is blocked by the S surfaceof the substrate 20 and thus void 41 is prone to be formed. Use of themanufacturing method of (a) of FIG. 14 enables avoiding formation of thevoid 41 that is ordinarily prone to be formed on the S surface of thesubstrate 20 even in atmosphere and that is to be a factor of decreasein the thermal conductivity, as much as possible. Thus the resin layermay be formed without insertion of equipment into a vacuum vessel, sothat workability may be greatly improved. In addition, costs related tointroduction of equipment may be reduced.

In the power supply devices 100 described as to Embodiments 1 to 9, theheat dissipation paths are ensured by potting (filling, molding) betweenthe S surface of the substrate on which the high-heat-generatingcomponent is mounted and the chassis of the power supply connected to astructure of an artificial satellite with the insulating liquid resinthat is resistant to space environment and that has the high thermalconductivity and by potting (filling, molding) on the screw part toconnect the substrate and the chassis with the insulating liquid resinthat is resistant to the space environment and that has the high thermalconductivity.

That is, curbing increase in a temperature of the component on thesubstrate is enabled by provision of the paths for the heat dissipationin addition to conventional thermal paths (in in-plane directions alongthe substrate) that depend on copper foil forming the circuit pattern inthe substrate and by resultant increase in capability for the heatdissipation to the chassis that is a casing of the power supply.

Description on Effects of Embodiments

The heat dissipation paths are ensured by the potting (filling, molding)around the high-heat-generating component or between the substrate onwhich the component is mounted and the chassis with the insulatingliquid resin that is resistant to the space environment and that has thehigh thermal conductivity. In addition to the conventional thermal paths(in the in-plane directions along the substrate) made of the circuitpattern formed of the copper foil ordinarily between tens of μm andseveral hundred μm, the paths for the heat dissipation are provided byconnection between the substrate and the chassis through the resinhaving the high thermal conductivity. The paths for the heat dissipationincrease the capability for the heat dissipation in the chassisdirection that is an off-plane direction from the substrate. Thuscurbing the increase in the temperature of the component on thesubstrate is enabled.

The insulating liquid resin having the high thermal conductivitycontains at least one of alumina, boron nitride, aluminum nitride,magnesium oxide, and beryllium oxide, as the inorganic filler providingthe high thermal conductivity.

The hardness of the cured insulating liquid resin is 70 or less (ShoreA).

The cured insulating liquid resin has the low-molecular componentvolatilization volume of 500 ppm or less in 300° C. heating and has theglass transition point of −20° C. or lower. In the cured insulatingliquid resin, as described above, silicone or urethane is the baseresin.

The configuration in which radiation paths are ensured by the thermallyconductive potting rein enables curbing increase in temperatures ofelectric components such as FET elements and enables decrease in sizesor increase in power of the power supply. Thus a structure with highheat dissipation that allows mounting of high-heat-generating componentseven with use of conventional substrates such as polyimide substrates orglass epoxy substrates may be provided.

Embodiment 10

With reference to FIGS. 15 to 20 , Embodiment 10 will be described. Inrelation to Embodiment 10, power supply devices 101-1, 101-2, 102-1,102-2, 102-3, and 102-4 will be described. Embodiment 10 relates to thepower supply devices in which a potential at a ground terminal 25 a ofthe electric component 25 and a potential on the chassis 10 are kept atdifferent potentials and in which the heat of the electric component 25is conducted to the chassis 10. In the power supply devices ofEmbodiment 10, the chassis 10 includes a raised part.

FIG. 15 illustrates a plan view and a sectional view of the power supplydevice 101-1. An upper drawing in FIG. 15 schematically illustrates theplan view of the power supply device 101-1 as seen looking in Z1direction. In the upper drawing in FIG. 15 , the filled through-holes 21are illustrated by solid lines. With reference to FIG. 15 , the powersupply device 101-1 of Embodiment 10 will be described.

The power supply device 101-1 includes the chassis 10, the substrate 20,and the chassis-side resin part 91.

Hereinbelow, the one surface 20 a and the other surface 20 b of thesubstrate 20 will be referred to as the surface 20 a and the surface 20b.

The electric component 25 is mounted on the substrate 20. The chassis 10has the chassis surface 11 that is the surface facing the surface 20 aof the substrate 20 and the raised part 14 which is raised from thechassis surface 11 toward the surface 20 a and whose end part 14 a withrespect to a raising direction 15 faces the surface 20 a without contactwith the surface 20 a. The raised part 14 is a heat transfer part 94.Heat generated in the electric component 25 is conducted to the raisedpart 14. The chassis-side resin part 91 is placed between the surface 20a of the substrate 20 and the end part 14 a of the raised part 14 and isconnected to the surface 20 a and the end part 14 a. The chassis-sideresin part 91 is cured insulating resin having a thermal conductivitybetween 1 W/mK and 10 W/mK inclusive.

As illustrated in FIG. 15 , the substrate 20 includes the filledthrough-holes 21 in which the through-holes penetrating from the surface20 a to the surface 20 b are filled with heat transfer material. Thechassis-side resin part 91 is connected to the one end part 21 a of eachof the filled through-holes 21 that appears on the surface 20 a and tothe end part 14 a of the raised part 14. The heat transfer material inthe filled through-holes 21 is either metal or cured insulating resinhaving a thermal conductivity between 1 W/mK and 10 W/mK inclusive.

In FIG. 15 , the chassis 10 includes an installation part 16 and theraised part 14 that is the heat transfer part 94. The ground terminal 25a of the electric component 25, together with the electric component 25,is fixed to the installation part 16 by the fixation screw 29. Theground terminal 25 a is thermally connected to the filled through-holes21. The chassis 10 includes an insulating body 17 and the electriccomponent 25 is fixed to the insulating body 17 by the fixation screw29. Specifically, the fixation screw 29 engages with internal threads 18formed in the insulating body 17 embedded in the chassis 10. Asillustrated in FIG. 15 , the filled through-holes 21 are not in contactwith the fixation screw 29.

In the raised part 14, an end surface 14 b of the end part 14 aprotrudes from the chassis surface 11 so as to be adjacent to thesurface 20 a of the substrate 20. The chassis-side resin part 91 isfilled between the end surface 14 b of the raised part 14 and thesurface 20 a of the substrate 20. The chassis-side resin part 91 isthermally connected to the filled through-holes 21 thermally connectedto the electric component 25.

The filled through-holes 21 are surrounded by a nonconductive region 20c of the substrate 20. The nonconductive region 20 c is a region havingno electrical conductivity in the substrate 20. As illustrated in FIG.15 , a creepage distance d1 of the nonconductive region 20 c has alength equal to or longer than a specified distance d from the groundterminal 25 a. Specifically, the creepage distance d1 along the surface20 a between an end of the ground terminal 25 a and a side surface 14 cof the raised part 14 has the length equal to or longer than thespecified distance d. Installation of the electric component 25 of highvoltage on the substrate 20 is enabled by the creepage distance d1 thatis equal to or longer than the specified distance d. Potentials at theelectrodes 26 and the ground terminal 25 a of the electric component 25differ from the potential on the chassis 10.

The power supply device 101-1 illustrated in FIG. 15 has a configurationin which the chassis-side resin part 91 is filled between the chassis 10provided with steps by the raised part 14 and the filled through-holes21 provided on the substrate 20. The configuration is characterized inthat the filled through-holes 21 are connected to “a side surface 14 dof the raised part 14 and the end surface 14 b of the raised part 14that are wall surfaces of the steps”.

The heat 8 of the electric component 25 is conducted from the filledthrough-holes 21 of the substrate 20 to the chassis-side resin part 91and from the chassis-side resin part 91 to the raised part 14 of thechassis 10. In addition, the heat 8 of the electric component 25 isconducted from around the fixation screw 29 through the substrate 20 tothe installation part 16.

In a power supply device having the configuration in which thethrough-holes formed on the substrate 20 and the chassis 10 areconnected by the resin so that the heat may be dissipatedunidirectionally, performance of the heat dissipation greatly depends onthe thermal conductivity of the resin.

In the power supply devices of Embodiment 10, by contrast, the convexsteps are provided on the chassis 10 by the raised part 14. InEmbodiment 11 to be described later, a concave recess 55 is provided onthe chassis 10.

By diffusion of the heat throughout the convex or concave wall surfacesthrough thermal diffusion in the resin, the heat dissipation paths areenhanced or the heat dissipation paths of the shortest routes are formedin the resin. The performance of the heat dissipation is improved bysuch heat dissipation paths and thus the power supply devices may beprovided with higher heat dissipation property.

FIG. 16 illustrates the power supply device 101-2 that is a modificationof the power supply device 101-1. In the power supply device 101-2, theelectric component 25 is covered with the component-side resin part 92.There is an only difference from the power supply device 101-1 in thisrespect. Such a configuration in which the electric component 25 iscovered with the component-side resin part 92 may be adopted.

FIG. 17 illustrates a plan view and a sectional view of the power supplydevice 102-1.

An upper drawing in FIG. 17 schematically illustrates the plan view ofthe power supply device 102-1 as seen looking in Z1 direction. In theupper drawing in FIG. 17 , positions of an end surface 14 b of a raisedpart 14-1 and the plurality of filled through-holes 21 are illustrated.In the upper drawing, the filled through-holes 21 are illustrated bysolid lines.

The substrate 20 includes the filled through-holes 21 in which thethrough-holes penetrating from the surface 20 a to the surface 20 b arefilled with heat transfer material. The raised part 14-1 is raised fromthe chassis surface 11 toward the surface 20 a in the chassis-side resinpart 91 and has the end part 14 a with respect to the raising direction15 facing the surface 20 a. The chassis-side resin part 91 is connectedto the one end part 21 a of each of the filled through-holes 21 thatappears on the surface 20 a.

In FIG. 17 , the end surface 14 b of the raised part 14-1 is in contactwith the nonconductive region 20 c in the surface 20 a of the substrate20. That is, the end surface 14 b of the end part 14 a of the raisedpart 14-1 is in contact with the nonconductive region 20 c. A region onthe surface 20 a where the one end part 21 a of each of the filledthrough-holes 21 does not appear forms the nonconductive region 20 c.

The raised part 14-1 is shaped like a column, for instance. The raisedpart 14-1 is shaped like a cylinder, a triangular column, a squarecolumn, or a polygonal column with five or more sides, as examples.

In FIG. 17 , the plurality of filled through-holes 21 are placed aroundthe nonconductive region 20 c. As in the upper drawing in FIG. 17 , thenonconductive region 20 c is surrounded by the plurality of filledthrough-holes 21.

As illustrated in FIG. 17 , the electric component 25 is placed over theplurality of filled through-holes 21. The raised part 14-1 is surroundedby the chassis-side resin part 91. Though the end surface 14 b of theraised part 14-1 is in contact with the surface 20 a of the substrate 20in FIG. 17 , the chassis-side resin part 91 may be filled between theend surface 14 b and the surface 20 a of the substrate 20.

As illustrated in FIG. 17 , the creepage distance d1 along the surface20 a between an end part of the end surface 14 b of the raised part 14-1and the filled through-hole 21 nearest thereto has a length equal to orlonger than the specified distance d, as with the power supply device101-1. The same applies to the power supply devices 102-2, 102-3, and102-4.

FIG. 18 is a sectional view of the power supply device 102-2.

FIG. 19 is a sectional view of the power supply device 102-3.

FIG. 20 is a sectional view of the power supply device 102-4.

The power supply device 102-2, the power supply device 102-3, and thepower supply device 102-4 differ from the power supply device 102-1 inthe shape of the raised part. In both of a raised part 14-2 of the powersupply device 102-2 and a raised part 14-4 of the power supply device102-4, shapes of sections taken with the raising direction 15 being anormal direction vary along the raising direction 15. In the raised part14-2 and the raised part 14-4, sizes of the shapes of the sectionsgradually decrease in the raising direction 15.

In the raised part 14-2 of the power supply device 102-2,cross-sectional areas (outside diameters) are varied. In the raised part14-2 of the power supply device 102-2, the cross-sectional areas aredecreased stepwise from the chassis surface 11 toward the surface 20 aof the substrate 20. The raised part 14-2 of the power supply device102-2 is shaped like a plurality of cylinders that differ in outsidediameter and that are built up in descending orders of the outsidediameter from the chassis surface 11 toward the surface 20 a of thesubstrate 20.

In the raised part 14-3 of the power supply device 102-3, the outsidediameters of the cross-sectional areas vary while alternating between along diameter and a short diameter from the chassis surface 11 towardthe surface 20 a.

The raised part 14-3 is spirally shaped or has wedged longitudinalsections and has perimeters forming an uneven shape, for instance.

In the raised part 14-4 of the power supply device 102-4, thecross-sectional areas are decreased gently or continuously from thechassis surface 11 toward the surface 20 a of the substrate 20. Theraised part 14-4 is shaped like a truncated cone or a truncatedpolygonal pyramid, for instance.

Description on Effects of Embodiment 10

In the power supply device 101-1 and the power supply device 101-2, thechassis-side resin part 91 connects the end surface 14 b of the raisedpart 14 and the surface 20 a. The creepage distance d1 has the lengthequal to or longer than the specified distance d. According to the powersupply device 101-1 and the power supply device 101-2, consequently, thepotential at the ground terminal 25 a and the potential on the chassis10 may be kept at different potentials and the heat of the electriccomponent 25 may be conducted to the chassis 10.

In the power supply device 102-1 to the power supply device 102-4, theend surface 14 b of the raised part 14 is in contact with the surface 20a. The chassis-side resin part 91 connects the end surface 14 b of theraised part and the surface 20 a. In addition, the creepage distance d1has the length equal to or longer than the specified distance d.According to the power supply device 102-1 to the power supply device102-4, consequently, the potential at the ground terminal 25 a and thepotential on the chassis 10 may be kept at different potentials and theheat of the electric component 25 may be conducted to the chassis 10.

Embodiment 11

FIG. 21 is a diagram illustrating a power supply device 103 according toEmbodiment 11. In the power supply device 103, steps are provided on thechassis surface 11, so that the recess 55 exists. In FIG. 21 , therecess 55 is represented by corners A to D. The recess 55 has a bottomsurface 11 a lower than the chassis surface 11.

The power supply device 103 includes the electric component 25, thesubstrate 20, the chassis 10 having the chassis surface 11 facing thesurface 20 a of the substrate 20, and the chassis-side resin part 91.The substrate 20 includes a solder leveler formation region 51, in whichsolder leveler 54 is formed in a region to be covered with the electriccomponent 25 on the surface 20 b that is on the back side of the surface20 a and includes a solder leveler formation region 51 in which thesolder leveler 54 is formed on the surface 20 a. The substrate 20includes a plurality of through-holes 52 which penetrate from thesurface 20 a to the surface 20 b, in which the solder leveler 54 isformed in inside surfaces, and which are placed in the region to becovered with the electric component 25.

The chassis-side resin part 91 is placed between the electric component25 and the solder leveler formation region 51 formed on the surface 20 bof the substrate 20, between the solder leveler formation region 51formed on the surface 20 a of the substrate 20 and the chassis 10, andinside the through-holes 52.

The chassis-side resin part 91 has a thermal conductivity between 1 W/mKand 10 W/mK inclusive and has a hardness of 70 or less on a Shore Ascleroscope. The chassis-side resin part 91 is cured insulating resin.

As illustrated in FIG. 21 , solder leveler 52 a formed in thethrough-holes 52 is connected to the solder leveler formation region 51formed on the surface 20 a and the solder leveler formation region 51formed on the surface 20 b.

As illustrated in FIG. 21 , the power supply device 103 is characterizedin that the chassis-side resin part 91 that is the cured resin is placedin sites to be described as (1), (2), and (3) below, as described above.The chassis-side resin part 91 therein has the thermal conductivitybetween 1 W/mK and 10 W/mK inclusive and has the hardness of 70 or lesson the Shore A scleroscope. The chassis-side resin part 91 is the curedinsulating resin.

(1) The chassis-side resin part 91 is placed between the electriccomponent 25 and the solder leveler formation region 51 formed on thesurface 20 b of the substrate 20. In the solder leveler formation region51, the solder leveler 54 is formed on a surface of copper plating 53applied on the surface 20 b of the substrate 20.(2) The chassis-side resin part 91 is placed between the solder levelerformation region 51 formed on the surface 20 a of the substrate 20 andthe chassis 10.(3) The chassis-side resin part 91 is placed inside the through-holes 52formed in the region of the substrate 20 directly beneath the electriccomponent 25.Therein, the copper plating 53 is applied on the inside surfaces of thethrough-holes 52 and the solder leveler 54 is applied on surfaces of thecopper plating 53.The inner side of the through-holes 52 has a laminated structure made ofthe copper plating 53 and the solder leveler 54.

In the power supply device 103, paths for heat dissipation extendingfrom the heat-generating electric component 25 to the chassis 10 areformed of the chassis-side resin part 91 that is the resin.

With use of the resin having a low hardness, stresses generated due tothermal shock and vibrations may be absorbed or relaxed by the resin.

Thus separation of each of the electric component 25, the substrate 20,the through-holes 52, and the chassis 10 from resin interfaces on thechassis-side resin part 91 may be reduced, so that reliability for theheat dissipation may be increased.

By interposition of the chassis-side resin part 91 having the lowhardness between the electric component 25 and the substrate 20,adhesion between the electric component 25 and the substrate 20 may beincreased and interfacial thermal resistance may be reduced.

It is desirable that a thickness of the chassis-side resin part 91 thatis the cured resin provided between the electric component 25 and thesubstrate 20 should be small, for decrease in the thermal resistance,and the thickness of the chassis-side resin part 91 is preferably equalto or lower than 0.25 mm.

The electric component 25 may be any of a resin molding, a ceramicpackage product, and a configuration covered with a metal case.

<Modification 1>

As the chassis-side resin part 91 illustrated in FIG. 21 , a liquidresin composition having a viscosity between 10 Pa·s and 300 Pa·sinclusive may be used.

The bottom surface 11 a of the chassis 10 or the surface 20 b of thesubstrate 20 is coated with the liquid resin composition having the highviscosity equal to or higher than 10 Pa·s coated thicker than usual.

The liquid resin composition having the high viscosity as coating isfilled into the inside of the through-holes 52 by a pressure generatedwhen the substrate 20 is fixed to the chassis 10 by the substratefixation screw 31 or when the electric component 25 is fixed to thesubstrate 20 by the fixation screw 29.

The viscosity of the liquid resin composition having the high viscosityequal to or higher than 10 Pa·s is between 10 Pa·s and 300 Pa·sinclusive, as described above.

More preferably, the viscosity of the liquid resin composition isbetween 50 Pa·s and 150 Pa·s because difficulty in fixation by the screwis increased with increase in the viscosity of the liquid resincomposition.

Even the resin having the viscosity equal to or higher than 10 Pa·s isfilled into the through-holes 52 during the coating.

The resin, however, may flow out of the through-holes 52 due to decreasein the viscosity when the resin is cured. In that case, the resin, ifcurable by heat, is semi-cured by being heated at a low temperature andis thereafter cured at a curing temperature higher than the temperaturefor semi-curing. Thus outflow from the through-holes 52 may be remedied.

On condition that the viscosity of the liquid resin composition is lowerthan 10 Pa·s, there is a fear that decrease in the viscosity during thecuring of the resin may prevent the resin from remaining inside thethrough-holes 52 so as to cause occurrence of unfilled regions or so asto make voids remain inside the through-holes 52 after the curing of theresin. In those cases, it is necessary to provide a wall that is to damthe resin so as to prevent the resin from flowing.

<Modification 2>

The cured resin may be formed of the same resin. The term “the same” in“the same resin” means that physical properties of the resin areconsidered the same.

That is, in case where

(1) a space between the electric component 25 and the solder levelerformation region 51 on the substrate 20,

(2) a space between the solder leveler formation region 51 formed on thesurface 20 a of the substrate 20 and the chassis 10, and

(3) the inside of the through-holes 52 of the substrate 20 provideddirectly beneath the electric component 25

are filled with different resins, there is a fear that separation oninterfaces between the cured materials may be caused by thermal shockbecause of difference in the physical properties such as hardness andcoefficient of thermal expansion among the cured resins. Problems suchas the separation may be avoided by filling of resins having the samephysical properties.

Embodiment 12

With reference to FIGS. 22 to 34 , power supply devices 104 ofEmbodiment 12 will be described. Based on differences in configurationsof a frame A and a frame B illustrated in FIG. 22 , seven power supplydevices 104-1 to 104-7 will be described as the power supply devices104. On condition that such distinction is not required, the powersupply devices 104-1 to 104-7 will be referred to as the power supplydevice 104.

Predominantly, characteristics of the power supply device 104 may bedescribed as (1) to (3) below.

(1) The power supply device 104 differs from the power supply device101-1 of FIG. 15 in configurations illustrated in the frame A to a frameC, as will be described later.

(2) In the power supply device 104, the electric component 25 and thechassis 10 are not in electrical contact with each other. The electriccomponent 25 is assumed to be a semiconductor package.

(3) The power supply device 104 is used in a spacecraft such asartificial satellite and influence of radiation in use in the spacecrafthas been taken into consideration for the power supply device 104.

For Embodiment 12, the one surface 20 a of the substrate 20 will bereferred to as a back surface 20 a and the other surface 20 b will bereferred to as a mounting surface 20 b.

FIG. 22 illustrates a sectional view of the power supply device 104-1.The power supply device 104-1 illustrated in FIG. 22 differs from thepower supply device 101-1 illustrated in FIG. 15 in the configurationsillustrated by the frame A, the frame B, and the frame C of dashedlines.

(a) The configuration illustrated by the frame A relates to a method offixing the electric component 25 and the substrate 20.

(b) The configuration illustrated by the frame B relates to a method offixing an end part of the substrate 20 and the chassis 10.

(c) The configuration illustrated by the frame C relates to a secondresin part 96 placed between the bottom surface of the electriccomponent 25 and the mounting surface 20 b of the substrate 20. Thesecond resin part 96 has the same resin that the chassis-side resin part91 has. In case where the chassis-side resin part 91 is placed betweenthe bottom surface of the electric component 25 and the mounting surface20 b of the substrate 20, the chassis-side resin part 91 serves as thesecond resin part 96.

For Embodiment 12, description will be given on six configurations thatare combinations of three types from type A1 to type A3 of theconfigurations illustrated by the frame A and two types of type B1 andtype B2 of the configurations illustrated by the frame B. Besides, thepower supply device 104-7 to be described later will be described as amodification. On condition that the configuration made of type A1 andtype B1 is represented as A1-B1, the six configurations may berepresented as A1-B1, A1-B2, A2-B1, A2-B2, A3-B1, and A3-B2. The powersupply device 104-1 corresponds to the configuration A1-B1.

FIG. 22 represents the sectional view and a plan view illustrating thepower supply device 104-1 of the configuration A1-B1.

FIG. 23 represents a sectional view and a plan view illustrating thepower supply device 104-2 of the configuration A1-B2.

FIG. 24 represents a sectional view and a plan view illustrating thepower supply device 104-3 of the configuration A2-B1.

FIG. 25 represents a sectional view and a plan view illustrating thepower supply device 104-4 of the configuration A2-B2.

FIG. 26 represents a sectional view and a plan view illustrating thepower supply device 104-5 of the configuration A3-B1.

FIG. 27 represents a sectional view and a plan view illustrating thepower supply device 104-6 of the configuration A3-B2.

FIG. 28 is a fragmentary enlarged view illustrating the configuration oftype A1.

FIG. 29 is a fragmentary enlarged view illustrating the configuration oftype A2.

FIG. 30 is a fragmentary enlarged view illustrating the configuration oftype A3.

FIG. 31 is a fragmentary enlarged view illustrating the configuration oftype B1.

FIG. 32 is a fragmentary enlarged view illustrating the configuration oftype B2.

FIG. 33 represents a sectional view and a plan view illustrating thepower supply device 104-7 that is the modification of the power supplydevice 104-6. FIGS. 22 to 27 and FIG. 33 are the sectional views and theplan views, which are similar to FIG. 15 , of the power supply devices104.

<Configuration of Power Supply Device 104-1>

With reference to FIGS. 22, 28, and 31 , the power supply device 104-1having the configuration A1-B1 will be described. The power supplydevice 104 that is used in a spacecraft includes the substrate 20, thechassis 10, the chassis-side resin part 91, the fixation screw 29, andan insulating member 60. The electric component 25 is mounted on themounting surface 20 b of the substrate 20. The electric component 25 iscovered with a metal package including copper as base material. Thechassis 10 has the chassis surface 11 that faces the back surface 20 a,which is the opposite side of the mounting surface 20 b and a threadedpart 10 a that has undergone threading. In FIG. 28 , the threaded part10 a is formed by digging on the surface of the chassis 10. Inside ofthe threaded part 10 a is threaded. The threaded part 10 a is formedintegrally with the chassis 10. The chassis-side resin part 91 is aninsulating resin-cured material placed between the back surface 20 a ofthe substrate 20 and the chassis surface 11, connected to the backsurface 20 a and the chassis surface 11, and with a thermal conductivitybetween 1 W/mK and 10 W/mK inclusive. The fixation screw 29 has a headpart 29 a and a threaded shaft part 29 b. Through the insulating member60, an open hole 61 in which the fixation screw 29 is to be placed isformed. The insulating member 60 includes such a material as glassepoxy, PTFE (Poly Tetra Fluoro Ethylene), or kapton.

The configuration of type B1 illustrated in FIG. 31 differs from theconfiguration illustrated in FIG. 15 in that the substrate fixationscrew 31 includes a washer 31 a. The other configurations are the sameas the configurations in a fixation method with use of the substratefixation screw 31 illustrated in FIG. 15 .

With reference to FIG. 28 , the configuration of type A1 will bedescribed. In the configuration of type A1, both the electric component25 and the substrate 20 are fixed to the chassis 10 with use of thefixation screw 29 and the insulating member 60. An open hole 25 d and anopen hole 20 d are respectively formed through the electric component 25and the substrate 20. The insulating member 60 includes a firstplacement part 60 a and a second placement part 60 b. The open hole 61penetrates the first placement part 60 a and the second placement part60 b. The first placement part 60 a is placed in a space 71 formed bycontinuous placement of the open hole 25 d of the electric component 25and of the open hole 20 d of the substrate 20. The second placement part60 b is placed outside the open hole 25 d of the electric component 25so as to be in contact with a peripheral edge 25 e of the open hole 25 dof the electric component 25. A washer 72 is attached to the fixationscrew 29. The fixation screw 29 fixes both the electric component 25 andthe substrate 20 to the chassis 10 by screw-coupling an end part 29 c ofthe shaft part 29 b, exposed in a direction toward the chassis 10 fromthe open hole 61 of the insulating member 60, to the threaded part 10 aof the chassis 10. In addition, the fixation screw 29 brings theelectric component 25 and the chassis 10 into electrical noncontact witheach other by being placed in the open hole 61 of the insulating member60.

<Configuration of Power Supply Device 104-2>

With reference to FIGS. 23, 28, and 32 , the power supply device 104-2having the configuration A1-B2 will be described. Description on theconfiguration of type A1 will be omitted because the configuration hasbeen described in relation to the power supply device 104-1. Withreference to FIG. 32 , the configuration of type B2 will be described.Type B2 differs from type B1 of FIG. 31 in inclusion of a columnar part10 b. In FIG. 32 , a heavy component 77 is illustrated. The heavycomponent 77 may be such a component as laminated ceramic capacitor ortantalum capacitor. The columnar part 10 b supports the heavy component77 and reduces vibrations caused by the heavy component 77. The columnarpart 10 b may be produced by machining of the surface of the chassis 10.The power supply device 104-2 includes the columnar part 10 b and acoupling screw 10 c. The columnar part 10 b is raised in shape of acolumn from the chassis surface 11, is threaded, and has an end surface,facing in a raising direction, to be connected to the back surface 20 aof the substrate 20. Inside of the columnar part 10 b is threaded. Awasher 10 d is attached to the coupling screw 10 c and the couplingscrew 10 c is screw-coupled to the columnar part 10 b. An open hole 20 eis formed through the substrate 20 at a position to be connected to thecolumnar part 10 b. The coupling screw 10 c fixes the substrate 20 tothe columnar part 10 b by penetrating the open hole 20 e formed at theposition to be connected to the columnar part 10 b and by beingscrew-coupled to the columnar part 10 b. The vibrations caused by theheavy component 77 may be reduced by provision of the columnar part 10b.

<Configuration of Power Supply Device 104-3>

With reference to FIGS. 24, 29, and 31 , the power supply device 104-3having the configuration A2-B1 will be described. Description on theconfiguration of type B1 will be omitted because the configuration hasbeen described in relation to the power supply device 104-1. Withreference to FIG. 29 , the configuration of type A2 will be described.In type A2 that lacks the chassis 10 under the substrate 20, the endpart 29 c of the shaft part 29 b of the fixation screw 29 exposed fromthe space 71 formed of the open hole 25 d and the open hole 20 d isfastened by a washer 74 and a nut 73. In the fixation screw 29, in thismanner, the shaft part 29 b is inserted into the space 71 formed by thecontinuous placement of the open hole 25 d of the electric component 25and of the open hole 20 d of the substrate 20 and the end part 29 c ofthe shaft part 29 b is thereby exposed from the space 71. The fixationscrew 29 fixes the electric component 25 and the substrate 20 to eachother by screw-coupling the exposed end part 29 c to the nut 73.

<Configuration of Power Supply Device 104-4>

The power supply device 104-4 illustrated in FIG. 25 has theconfiguration A2-B2. Type A2 is as has been described in relation to thepower supply device 104-3 and type B2 is as has been described inrelation to the power supply device 104-2.

<Configuration of Power Supply Device 104-5>

The power supply device 104-5 illustrated in FIG. 26 has theconfiguration A3-B1. With reference to FIG. 30 illustrating type A3, theconfiguration of type A3 will be described. In type A3, compared withtype A1 of FIG. 28 , the threaded part 10 a has a columnar configurationsimilar to the columnar part 10 b. The threaded part 10 a in FIG. 30 maybe produced by machining of the surface of the chassis 10, as with thecolumnar part 10 b.

<Configuration of Power Supply Device 104-6>

The power supply device 104-6 illustrated in FIG. 27 has theconfiguration A3-B2. The configuration of type A3 is as has been statedin description on the power supply device 104-5. The configuration oftype B2 is as has been stated in description on the power supply device104-2.

<Configuration of Power Supply Device 104-7>

In the power supply device 104-7 illustrated in FIG. 33 , in contrast tothe power supply device 104-6, the columnar threaded part 10 a is acomponent separate from the chassis 10. The threaded part 10 a is fixedto the chassis 10 by a screw 75 and a washer 76 from a side of a backsurface of the chassis 10. An inside surface of the threaded part 10 ais threaded. An installation structure for the threaded part 10 a on aside of the substrate 20 is the same as an installation structure in thepower supply device 104-6. Though the power supply device 104-7 is thecombination with the configuration of type B2, the configuration havingthe columnar threaded part 10 a that is the separate component may becombined with the configuration of type B1. Though the columnar part 10b of type B2 is formed integrally with the chassis 10, the columnar part10 b of type B2 may be a component separate from the chassis 10, as withthe threaded part 10 a of the power supply device 104-7.

Subsequently, relation between the power supply device 104 and radiationwill be described. The power supply device 104 that is placed in aspacecraft is exposed to radiation. Permeability of the radiation suchas alpha ray, gamma ray, electron beam, and neutron beam may be weakenedby setting of a thickness at 2 mm or more of the chassis 10 where theelectric component 25 is to be provided. It is desirable that a totalradiation dose the power supply device 104 receives for 15 years shouldbe 5 Mrad or less, in terms of prevention against alteration of thechassis-side resin part 91 and the second resin part 96, and it is moredesirable that the total radiation dose should be 2 Mrad or less, interms of prevention against malfunction and characteristic degradationof analog semiconductors. In the power supply device 104 in whichdigital semiconductors are installed, furthermore, it is the mostdesirable to set the total radiation dose the power supply device 104receives for 15 years in a range between 0.1 Mrad and 1 Mrad inclusive,in terms of prevention against malfunction and characteristicdegradation of the digital semiconductors.

The chassis-side resin part 91 has a Shore A hardness of 50 or less,after being cured, and has a Shore A hardness of 70 or less, after beingexposed to the total radiation dose of 5 Mrad to be received for 15years. The chassis-side resin part 91 tends to have progressing hardnessbecause exposure to the radiation may cause unreacted active groups toreact so that polymerization may progress. Exposure to excess radiationover 50 Mrad, however, may cause cleavage of organic groups in sidechains, progression of cross-linkage leading to shrinkage of resin, andremarkable increase in the hardness. Occurrence of the resin shrinkagemay result in separation on interfaces between highly thermal conductiveresin and adherend such as the chassis, the substrate, the electriccomponent, or solder leveler and thus may result in deterioration inheat dissipation. Presence and absence of such a phenomenon of the resinmay be determined based on decrease in peaks of the organic groups inthe side chains through a structural analysis with FT-IR analysis. Ithas been confirmed through the structural analysis with the FT-IRanalysis that there is no change in peak intensities of the organicgroups in the side chains, meaning that there is no occurrence of thecleavage of the organic groups in the side chains, on condition that thetotal radiation dose the chassis-side resin part 91 receives for 15years is 5 Mrad or less. Therefore, desirable use without deteriorationin performance of the heat dissipation may be ensured on condition thatthe total radiation dose the chassis-side resin part 91 receives for 15years is 5 Mrad or less.

Based on above, an upper limit of the total radiation dose the powersupply device 104 receives for 15 years is any of 5 Mrad, 2 Mrad, and avalue in the range between 0.1 Mrad and 1 Mrad inclusive. Besides, thechassis-side resin part 91 has the Shore A hardness of 50 or less, afterbeing cured, and has the Shore A hardness of 70 or less, after beingexposed to the radiation with the total radiation dose of 5 Mrad to bereceived for 15 years.

FIG. 34 is a diagram illustrating shielding of radiation dose. FIG. 34is the diagram illustrating an example of an artificial satellitestructure 230 disclosed in JP 2003-291898, for instance. In FIG. 34 ,electronic equipment 208 is electronic equipment to be installed in anartificial satellite. The electronic equipment 208 corresponds to theelectric component 25. A central cylinder 221 is shaped like a cylinderplaced at center of the artificial satellite structure 230. Web panels222 are installed on outside of the central cylinder 221 so as to extendradially and so as to parallel a center axis of the central cylinder221. A ceiling panel 223 is installed on top ends of the centralcylinder 221 and the web panels 222 so as to extend horizontally andforms a ceiling of the artificial satellite structure 230 that is shapedlike a box. A base panel 224 is installed from underside of the centralcylinder 221 so as to extend horizontally and forms a bottom plate ofthe artificial satellite structure 230 that is shaped like the box.Outer surface panels 225 are installed on the web panels 222, theceiling panel 223, and the base panel 224 and form outer surfaces of theartificial satellite structure 230.

The power supply device 104 and other electronic equipment are placedaround the central cylinder 221. By use of above components as shieldsagainst the radiation, the radiation dose to which the power supplydevice 104 and other electronic equipment are to be exposed in alifespan of the artificial satellite that is a spacecraft may beadjusted. By use of the chassis-side resin part 91 under an adjustedenvironment, deterioration of the chassis-side resin part 91 underinfluence of the radiation in the lifespan of the artificial satellitemay be reduced.

Effects of Embodiment 12

(1) The power supply device 104 of Embodiment 12 includes thechassis-side resin part 91 and thus may dissipate heat of the powersupply device by a simply-configured heat dissipation structure.

(2) In the power supply devices 104-1, 104-2, and 104-5 to 104-7, thesubstrate and the electric component are fixed by the fixation screw tothe chassis through the insulating member 60. As a result, the spacepower supply devices having vibration resistance may be provided whilethe electrical noncontact between the chassis and the electric componentis ensured.(3) The electric component 25 and the substrate 20 are fixed to eachother by the nut 73 in the power supply device 104-3 and the powersupply device 104-4 and thus the electric component 25 and the substrate20 may be fixed even in the power supply device 104 with specificationsincluding a space between the substrate 20 and the chassis 10.(4) In the power supply device 104 of Embodiment 12, the upper limit ofthe total radiation dose to be received for 15 years is restricted so asto be any of 5 Mrad, 2 Mrad, and a value in the range between 0.1 Mradand 1 Mrad inclusive. Thus the total radiation dose to be received for15 years is restricted and therefore troubles due to deterioration ofthe chassis-side resin part 91 caused by the radiation may be prevented.Consequently, an effect of the heat dissipation by the chassis-sideresin part 91 may be maintained for 15 years.

Though Embodiment 1 to Embodiment 12 have been described above, thoseembodiments relate to the space power supply devices and two or more outof the embodiments may be combined. Alternatively, one of theembodiments may be partially embodied. Alternatively, two or more out ofthe embodiments may be partially embodied in combination. Note that thepresent invention is not to be limited by those embodiments but may bemodified in various manners as appropriate.

REFERENCE SIGNS LIST

8: heat; 10: chassis; 10 a: threaded part; 10 b: columnar part; 10 c:coupling screw; 10 d: washer; 11: chassis surface; 11 la: bottomsurface; 12: screw hole; 13: area; 14, 14-1, 14-2, 14-3, 14-4: raisedpart; 14 a: end part; 14 b: end surface; 14 c: side surface; 15: raisingdirection; 16: installation part; 17: insulating body; 18: internalthread; 20: substrate; 20 a: one surface; 20 b: the other surface; 20 c:nonconductive region; 20 d: open hole; 20 e: open hole; 21: filledthrough-hole; 21 a: one end part; 21 b: the other end part; 23:thermally-conductive material; 24: adhesive; 25: electric component; 25a: ground terminal; 25 d: open hole; 25 e: peripheral edge; 26:electrode; 27-1: cured insulating resin; 27-2: resin; 27-3, 27-4: curedresin; 28-1: electrode connection part; 28-2: chassis connection part;28-3: through-hole connection part; 29: fixation screw; 29 a: head part;29 b: shaft part; 29 c: end part; 30: fixation part; 31: substratefixation screw; 31 a: washer; 32 a: solder; 32 b: screw; 33: springfixture; 41: void; 42: screw; 51: solder leveler formation region; 52:through-hole; 53: copper plating; 54: solder leveler; 55: recess; 60:insulating member; 60 a: first placement part; 60 b: second placementpart; 61: open hole; 71: space; 72: washer; 73: nut; 74: washer; 75:screw; 76: washer; 77: heavy component; 91: chassis-side resin part; 92:component-side resin part; 93: contact resin part; 94: heat transferpart; 96: second resin part; 100, 100-1, 100-2, 100-3, 100-4, 100-5,100-6, 100-7, 100-8, 101-1, 101-2, 102-1, 102-2, 102-3, 102-4, 103, 104,104-1, 104-2, 104-3, 104-4, 104-5, 104-6, 104-7: power supply device;208: electronic equipment; 221: central cylinder; 222: web panel; 223:ceiling panel; 224: base panel; 225: outer surface panel; 230:artificial satellite structure

The invention claimed is:
 1. A power supply device to be used in aspacecraft, the power supply device comprising: a substrate on which anelectric component is mounted on a mounting surface; a chassis having achassis surface facing a back surface which is the opposite side of themounting surface and a threaded part having undergone threading; achassis-side resin part being an insulating resin-cured material to beplaced between the back surface of the substrate and the chassis surfaceso as to be connected to the back surface and the chassis surface, thecured insulating resin with a thermal conductivity between 1 W/mK and 10W/mK inclusive; a fixation screw having a threaded shaft part; and aninsulating member through which an open hole in which the fixation screwis to be placed is formed, wherein open holes are formed through theelectric component and the substrate, the insulating member includes afirst placement part placed in a space formed by continuous placement ofthe open hole of the electric component and the open hole of thesubstrate and a second placement part placed outside the open hole ofthe electric component so as to be in contact with a peripheral edge ofthe open hole of the electric component, the fixation screw fixes boththe electric component and the substrate to the chassis byscrew-coupling an end part of the shaft part, exposed in a directiontoward the chassis from the open hole of the insulating member, to thethreaded part of the chassis and brings the electric component and thechassis into electrical noncontact with each other by being placed inthe open hole of the insulating member, the substrate includes aplurality of filled through-holes in which a plurality of through-holespenetrating from the back surface, which is one surface to the mountingsurface, which is the other surface are filled with a heat transfermaterial, and the chassis and a ground terminal of the electriccomponent are kept at different potentials.
 2. The power supply deviceaccording to claim 1, wherein the threaded part of the chassis is formedintegrally with the chassis.
 3. The power supply device according toclaim 1, wherein the threaded part of the chassis is a componentseparate from the chassis.
 4. The power supply device according to claim1, further comprising: a columnar part which is raised in shape of acolumn from the chassis surface, is threaded, and has an end surface,facing in a raising direction, to be connected to the back surface ofthe substrate; and a coupling screw to be screw-coupled to the columnarpart, wherein an open hole is formed through the substrate at a positionto be connected to the columnar part, and the coupling screw fixes thesubstrate to the columnar part by penetrating the open hole formed atthe position to be connected to the columnar part and by beingscrew-coupled to the columnar part.
 5. The power supply device accordingto claim 4, wherein the columnar part is formed integrally with thechassis.
 6. The power supply device according to claim 4, wherein thecolumnar part is a component separate from the chassis.
 7. The powersupply device according to claim 1, wherein an upper limit of a totalradiation dose to be received for 15 years is 5 Mrad or less.
 8. Thepower supply device according to claim 1, wherein the chassis-side resinpart has a Shore A hardness of 50 or less, after being cured, and has aShore A hardness of 70 or less, after being exposed to radiation withthe total radiation dose of 5 Mrad to be received for 15 years.
 9. Apower supply device to be used in a spacecraft, the power supply devicecomprising: a substrate on which an electric component is mounted on amounting surface; a chassis having a chassis surface facing a backsurface which is the opposite side of the mounting surface; achassis-side resin part being an insulating resin-cured material to beplaced between the back surface of the substrate and the chassis surfaceso as to be connected to the back surface and the chassis surface, thecured insulating resin with a thermal conductivity between 1 W/mK and 10W/mK inclusive; and a fixation screw having a threaded shaft part,wherein open holes are formed through the electric component and thesubstrate, the fixation screw, having the shaft part inserted into aspace formed by continuous placement of the open hole of the electriccomponent and the open hole of the substrate and having an end part ofthe shaft part exposed from the space, fixes the electric component andthe substrate each other by screw-coupling the exposed end part to anut, the electric component and the chassis are not in electricalcontact with each other, the substrate includes a plurality of filledthrough-holes in which a plurality of through-holes penetrating from theback surface, which is one surface to the mounting surface, which is theother surface are filled with a heat transfer material, and the chassisand a ground terminal of the electric component are kept at differentpotentials.